[Comparison of glaucoma drainage implants]

Glaucoma drainage devices (tubes, GDI or GDD) are nowadays an important surgical option in the treatment of refractory glaucoma. They are frequently used in cases where previous glaucoma surgery has failed or in patients with a history of conjunctival scarring where other procedures are contraindicated or simply not possible. This article looks at the evolution of glaucoma drainage implants from the very beginning to the multiple designs, experiences and research studies that have made tubes an essential part of the armamentarium of modern glaucoma surgeons. The article describes the first concepts and then proceeds to the first commercialized devices which led to the widespread use of tubes such as Molteno®, Baerveldt® and Ahmed®. Finally, it looks at the innovations that have been carried out, particularly over the last decade with the advent of new tubes, such as Paul®, eyeWatch® and Ahmed ClearPath®. The factors associated with the success and failure of GDD surgery, including the indications, are different from those for trabeculectomy and increasing experience and larger amounts of data have helped glaucoma surgeons to become more comfortable with selecting the most appropriate procedure for the individual patients.